NEW BOOKS Crystal Chemistry. By CHARLESW. STILLWELL. 431 pp. New York: McGrawHill Book Company, Inc., 1938. Price: $4.50. Crystal chemistry is a new branch of chemistry. The author, in his preface, defines i t as follows: “Crystal chemistry is the study of (1) the laws governing the arrangement of atoms in solids and (2) the influence of the arrangement and electronic structure of the atoms upon the physical and chemical properties of the solid.” It had its beginning only about ten years ago when Pauling and Goldschmidt, independently, began the correlation of t h e accumulated d a t a and results of crystal structure analysis. The principles of crystal chemistry already make necessary a revision of some of the basic concepts of chemistry. Hence the importance of this new science to every chemist, both in research and teaching, is only too obvious. The reviewer wishes t o state immediately that the author has produced a very excellent book which can be most enthusiastically recommended. Many have probably read the author’s splendid series of papers on this subject which appeared in the Journal of ChemicaE Education in 1936-37. These papers form the basis of parts of four chapters. The chapter titles are as follows: I, Introduction; 11, The Sizes of Atoms and Ions; 111, The Structures and Properties of the Elements: The Metallic State; IV, The Kature of Alloys; V, The Structures of Binary Compounds; VI, The Properties of Binary Compounds; VII, The Structures of Ternary Compounds; VIII, The Structures of the Silicates; IX, The Structures of Werner Compounds; X, Isomorphism, Mixed Crystals, Polymorphism; XI, The Structures of Organic Crystals; X I I , Natural Fibers; X I I I , Synthetic Fibers. KO space is devoted to discussion of the methods of crystal analysis. In the introduction the author first very briefly discusses a few fundamentals of crystallography. The remainder of the chapter is then spent in giving the reader a brief and suggestive sketch of crystal chemistry. In fact the author points out, in his preface, that the material of the introduction is intended for use in the introductory course in chemistry. The fundamentals outlined in the introduction are then developed in greater detail in the remainder of the book, making i t as a whole very suitable for advanced courses. The book contains an immense amount of data in the form of 122 tables. In addition there are 72 figures (charts, diagrams, photogmphs, etc.) which are almost without exception well chosen and well reproduced. The list of references is not exhaustive, but it is sufficiently complete t o form a basis for a more detailed study of the subject. There appear t o be very few errors of a factual nature, but several obvious typographical errors have crept in. In conclusion, the reviewer again wishes to state that all chemists, and readers interested in chemistry, will find this an excellent and timely book. HAROLD P. KLUG. Grundzdge der Theorie ungesaftigler und aromatischer Verbindungen. By E . H ~ C K E L . 21 x 15 cm; 160 pp. Berlin: Verlag Chemie, G.m.b.H., 1938. Price: 6 RM. This is a reprint of an article appearing in Zeitschrift fdr Elektrochemie (volume 43). The author attempts to explain with a minimum of mathematics the ideas on which the recent theories of “resonance” are based, and the principal results which have 863
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been obtained. One of his first points is that the analogy b e t w e n “resonance” in molecules and resonance in the theory of forced oscillations is remote; he therefore prefers t o use “mesomerism,” a word originally suggested by Ingold. The first half of the book explains briefly the pair and orbital methods of approximation t o the energy of formation of polyatomic molecules, and applies them to ethylene and t o benzene and other ring compounds. A chapter on free radicals follows, and some interesting speculations on di-radicals are mentioned. The subject matter of chapter V is the reactivity properties of various unsaturated and aromatic compounds. Very simple calculations, for example, give the most likely point of attachment of a first and then a second halogen atom t o a number of unsaturated rings or conjugated chains. Other more complicated reactions are also considered. The last chapter gives a brief sketch of the theory of ring compounds in which one of the corner atoms is not carbon. Polar effects of unknown size here make the theory very uncertain. In the opinion of the reviewer, several topics have been omitted which should have been included. One of the early chapters should have explained the difference between the valency state of carbon and the normal state, and hence lead up t o an estimate of the energy of reorganization (Van Vleck’s theory). This chapter, or another, should have given a brief account of the localized bonds. Another possible omission is t h a t no estimate of the resistance of the ethylene molecule t o twisting is made, although the most &able position is stated t o be planar. A further criticism is t h a t no matter in what form comparisons of “calculated” and observed energies of formation of long series of aromatic and unsaturated molecules are presented, far too good an impression of the accuracy of the theory is given. What is being tested by these comparisons is not the theory, but the constancy of bond energies from molecule t o molecule. When the molecule is mesomeric, as a matter of observation, some of the bonds gain slightly in stability, and the theory of mesomerism in its present form seems t o offer a convenient semi-empirical method for estimating these gains. Cnless this is made very clear t o the general reader, he will get the impression t h a t the theory is almost rigorously precise, whereas all t h a t may be said at present, is t h a t apparently it gives precise results. The boob is recommended because t,hose topics \vit,h which it deals arc covered very well. Any later book on mesomerism will be able t o make considerable use of the pyesent work. It would seem desirabIe, however, that in a more extended account of the subject ot,her important topics should be mentioned, such as the difference between the valency state of carbon and the normal state, localized bonds, and a more detailed statement of the resist,ance of molecules such a s t h a t of ethylene t o twisting. More emphasis might also be laid on the semi-empirical character of some of the calculations of the present time. W. G. PENNEY.
Duodecimal Arithmetic. By GEORGES . TERRY.407 pp. S e w York: Longmans, Green and Co., 1938. Price: $7.50. It has often been pointed out t h a t the operations of arithmetic would be simplified in many respects if our counting were based on some other number t h a n ten. The base twelve, in particular, has important advantages in its divisibility by 2, 3, 4, and 6. One must be an enthusiast, nevertheless, in order t o look hopefully toward widespread adoption of a new system of numeration for the purposes of school, commerce, and science. The author of Duodecimal Arithmetic is such an enthusiast, and has given as favorable a presentation of the case for the duodecimal system as can well be imagined. The verbal argument is brief, temperate, and judicious. The fundamental
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arithmetical processes are explained and illustrated in a notation using the digits 0, 1, 2, . . . 9, together with the symbols X and E, or modifications of them, for the numbers ordinarily called ten and eleven. The equation 34 121 = 155, for example, becomes 2X X1 = 10E. The introduction is followed by an extensive set of tables including powers and roots, reciprocals, logarithms, and the natural values and logarithms of trigonometric functions, largely t o nine places of duodecimals, designed t o facilitate an adequate trial of the notation for purposes of actual calculation. The text and tables, excellent in arrangement, convenient t o the hand and agreeable t o the eye, will be interesting and instructive t o many students who examine them with less serious purpose than the ultimate reform of all arithmetic. DUNHAM JACKSON.
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Expresion de la Reaccion y Calculos Potenciometricos e n la Determinacion del p H . By DOMIXGO GIRIBALDO.271 pp. Montevideo: Casa A Bareiro y Ramos, 1937. This book is divided into three parts. In the first part, involving eight chapters, Ihe reaction 1pH) of aqueous solutions is discussed with emphasis on the expression p R = log H+ - log OH-. The dissociation and neutralization curves of ampholyte8 are described in detail. The second part (nine chapters) deals mainly with principles of potentiometry, the calculations involved, and the potentiometric determination of pH with the hydrogen, quinhydrone, and glass electrodes. The last part presents tables with explanatory notes which are useful in the calculations. The book is quite up to date and is a good addition to the literature on this subject in the Spanish language. I. M. KOLTHOFF. Qualitatiue Analyse mil Hilfe von Tupjelreaktionen. By FRITZFEIGL. 3rd edition. 551 pp. Leipzig: Akademische Verlagsgesellschaft, 1938. Price : bound, 30 RM. Feigl’s book does not need a recommendation. The rapid appearance of the third edition after the second one (1935), with the English and Russian translations of the latter, shows without doubt that the book is universally considered a standard work. I t occupies a unique place in qualitative analysis. I t serves as a guide for further research in the development of new (mainly) organic reagents and tests and it contains a wealth of information regarding the identification and separation of inorganic and organic ions and molecules. To the theoretical part have been added chapters on “fluorescence analysis and spot reactions” and “effect of substitutions by heavy groups on solubility.” The practical part occupies about 40Opages and gives an extensive review of the detection of inorganic cations and anions, of systematic schemes of separation, of the detection of elements and reactive groups in organic compounds and of a number of organic substances. The last chapter deals with the application of spot tests t o purity tests and detection of traces of various constituents in minerals, ores, alloys, etc. Finally, an extensive alphabetical table is given in which the reagents and sensitivities of the reactions of the various inorganic and organic components are summarized with references to pages in the text. T h e book is n tribute to Feigl’s pioneer work in the field. I t is a sad coincidence that the publication of this third edition occurred at, the time when the author with many other scholars was dismissed from the University of Vienna for racial or political reasons. The reviewer expresses the wish that chemists whose views and outlook are determined mainly by the search for truth will cooperate in finding a deserving position for the author which will enable him to continue his important researches in a truly scientific environment,. I. M. KOLTHOFF.
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Numerical Problems i n Advanced Physical Chemistry. By J. H. WOLFENDEN. 227 pp. London: Oxford Press, 1938. Price: $2.75. The 133 problems which make up this list have been selected from the original literature to illustrate the principal divisions of physical chemistry. In the reviewer’s opinion the selection has been made wisely and with remarkably little bias. The essential dateof each problem are accompanied by a brief but valuable discussion of the immediate hackground of the subject. The usefulness of the book is greatly increased by the inclusion of references to the original literature, t o specialized monographs, and to a number of the better known texts of physical chemistry. Answers t o the problems are furnished a t the end of the hook. Any independent student of general physical chernistry should find this book helpful and stimulating. In this country it will probably be used most extensively by candidates for the doctor’s degree in reviewing their elementary physical chemist r y in preparation for examimtion. ROBERTLIVINGSTON. Newer Methods of Volumetric Chemical Analysis. By E. BRENNECKE, iY.H. FURMAN, K. STAMM,R. L.4NG, and K. FAJANS; WILHELMBBTTGER,Editor. Translated by Ralph E. Oesper. 268 pp. ?Jew York: D. Van Nostrand Company, Inc., 1938. Price: $3.75. This volume is the English translation of the second German edition of Neuere massanalytische Methoden, one of the series Die chemische Analyse. The book is a collection of discussions of recent developments in volumetric analysis embracing the following topics: elimination of the titration error in acidimetric and alkalimetric titrations, ceric sulfate as a volumetric oxidizing agent, alkaline permanganate solution as volumetric oxidizing a,gent, iodate and bromate methods (including Manchot’s bromometric method), chromous solutions as volumetric reduc,ing agents, oxidation-reduction indicators, and adsorption indicators fur precipitation titrations. Comprehensive bibliographies are appended t o each section. As stated by the editor in the preface, “These topics have been treated with two objectives in mind: (a) exposition of the theory underlying the new method, so that an insight may be gained into the reasons for the way in which the subject has been developed, and (b) the presentation, so far as possible, of an exact set of directions for the performance of particular analyses.” In reading this book one cannot but be struck by the important r61e played by physicochemical principles in the development of modern methods of chemical analysis. The topics treated do not exhaust the field and one might wish that other phases of the subject (for example, induced reactions) had been included. The translation has been excellently done. A number of minor errors of typographical nature were noted. “Quinquevalent” has been spelled “quinquivalent.” I n the footnote on page 99, the journal reference should be “2;. angew. Chem.,” not “Z, anorg. Chem.” E. B. SANDELL. Photoelements and their Application. By BROKOLAKGE. Translated by Ancel St. John. New York: Reinhold Publishing Corp., 1938. Price: $5.50. This book is the first covering the whole field of semiconduction photo cells. About 238 references are cited and commented upon. The book is divided into two sections, The first deals with the development and properties of the photoelements and the second with the applications. The first section gives an integrated picture of the development and properties of what
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Dr. Lange calls “photoelements”, including “barrier-layer cells, photovoltaic cells, crystal cells, Becquerel cells, etc.’’ T h e brief historical development is followed by a review of the various theories concerning t h e semiconductor photoeffect. The Shottky (barrier film) and t h e Teichmann (field funnel) theories are correlated, the electrochemical theory discarded, and the electron diffusion theory, using an insulating layer, stressed. I t seems unfortunate t o the reviewer t h a t the difference of the insulating layer and the barrier layer is stressed. Although the cuprous oxide front wall cell mentioned on page 73 does not show unipolar conductivity, both the German electrocell and the Weston phototronic cell do show unipolar conductivity. Both of these are frontwall selenium cells. The conclusion would seem t h a t the idea of a barrier film cannot be dismissed so easily. In explaining the photo E . M . F . by electron concentration gradients only the concentration in the semiconductor and the insulating layer are considered, although there would be considerable electron concentration in the metal layer above it. It is this factor t h a t the barrier layer has tried t o explain. T h e chapter on physical properties coordinates a vast amount of literature of the past few years. I t will be very valuable t o anyone desiring t o review these when time for review is limited. The characteristics of the cell-photocurrent, photopotential, and cell resistance as related t o intensity of illumination as well as t o each other-are described and the curves given. The effect of temperature, wave length of incident light, polarized light, x-rays, cathode rays, and magnetic field are discussed, similarly the frequency relations and capacitive properties. The stability and fatigue values are clearly separated from each other. The effect of fatigue is eliminated in stability measurements by allowing a two-hour dark recovery period before measurement. Of interest t o physicists may be the method applied in determining the work function and the threshold wave lengths by indirect measurements. The first section of the hook serves as an excellent bibliography up t o 1935; however, a great deal of work has been done since t h a t date and this is not covered by the translator. The second section deals entirely with construction and applications. T h e details on construction are very incomplete and would offer little help t o anyone interested in this art. The description of applications is, however, very complete. The section is very similar to a manufacturer’s publication, and as such stresses particularly the apparatus of the German companies. The section is, however, very readable and has many interesting suggestions for manufacturers or chemists interested in control instruments. Exposure meters for photographic control (some semiautomatic on motion picture cameras), for copying, and for photomicrographic use are described. Transparency and density meters, micro- and spertro-photometers, reflection and gloss meters are common uses. Of great interest t o the chemist is the accurate measurement by differential means of absorption of light in colorimetry. The use for analytical work of this type is rapidly growing. The application of photoelement cells is described for long distance transmission of circular or straight scales, for industrial cases where t h e position of the original instrument is fixed. Other applications include auxiliary control for balances, switching and signal devices, etc. In some of these cases the advantages of the photoelement as opposed t o the photoelectric vacuum tube are pointed out. In conclusion the author suggests uses in the fields of chemistry, physics, astronomy, bioclimatology, meteorology, oceanography, hydrography, medicine, and electrical engineering and also as a source of energy.
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The latter half of the book is primarily an advertising medium and should be treated as such. The first half is an interesting integration of the knowledge and theory of the semiconductor photocell a t the time the book was written. JOHNSTONE S. MACXAY. The Catalytic Action of Surfaces. By J. E. XYROP. Second edition. 103 pp. 20 x 27 cm. Copenhagen, Denmark: Levin and Munksgaard, 1937. Price: 10 Danish krone. The thesis t h a t the author attempts t o develop and support by experimental and theoretical arguments is stated in the following two postulates: “Postulate A. I n a chemical reaction furthered considerably by the presence of a surface the surface is a t the temperature in question able to ionize those molecules among the reactants most difficult t o ionize and the surface will cause a strong adsorption a s ions formed a r e attracted by the surface. Postulate B. A surface able to ionize molecules of a gas or liquid and hence able t o yield a strong adsorption produces an increased adsorption when the molecules are substituted by others having a lower ionization potential assuming t h a t all other conditions are the same.” Since new points of view in catalysis are always welcome, this book with its eightythree references and its partial summary of experimental work in catalysis will probably be found interesting t o many readers. T o all i t should prove thoughtprovoking. However, in the reviewer’s opinion, the book is unconvincing and in some respects carelessly written. The attempted substantiation of the ideas of postulates A and B by presentation of catalytic data is frequently marred by an evident lack of critical judgment or a careless scrambling of experimental results. The following excerpt from page 23 will suffice as an illustration: “When hydrogenation of the (carbon) monoxide takes place on copper, methane is produced and, as the ionization energy of these products is between 13.7 and 15 volts, none of them take up the space of the surface zone preferentially. If three volumes of hydrogen and one volume of nitrogen pass over a surface of nickel or one of iron a t certain temperatures and pressures ammonia is produced and the b m t result is obtained when the adsorption takes place in the proportion of 3 : l . In accordance with technical results this takes place on iron.” To appraise this statement properly one must bear in mind t h a t copper is ordinarily considered incapable of hydrogenating carbon monoxide t o methane, t h a t the ionization potentials of H,O,CO,CH,, and H, are 12.7, 14.1, 14.5, and 15.37 volts, respectively, and t h a t the separate adsorption measurements for hydrogen and nitrogen on iron catalysts do not reveal a 3: 1 ratio a t any temperature a t which the synthesis of ammonia takes place, a s far as the reviewer has been able t o ascertain. K O source of information was cited in connection with the paragraph from which the above quotation was taken. The mathematical formulations in chapter I1 are insufficiently explained t o enable the reviewer t o assess their value. They are entirely unronvincing in their present form. However, it se8ms t h a t no amount of revision or clarification of this or other portions of the book so far discussed will establish the case t h a t the author is attempting t o support, unless the conclusions arrived a t in chapter VI1 are sound. In this chapter on “Metals” the author takes upon himself the task of explaining how, for example, iron or nickel catalysts are able t o ionize impinging molecules whose ionization potentials are a s high as 17 or 18 volts. Final judgment in this connection will have t o be left t o the mathematical physicist.
P. H. EMMETT.
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Hydrophobic CoZZoids. Symposium on the Dynamics of Hydrophobic Suspensions and Emulsions, held a t Utrecht on the 5th and 6th of Kovember, 1937, under the auspices of the Colloidchemistry Section of the Kederlandsche Chemische Vereeniging. 188 pp. Amsterdam: D. B. Centen’s Uitg. Mij. K.C.>1938. Kew York: Sordemann Publishing Co., Inc., 1938. Price: $2.50. From a social and propagandistic point of view large scientific gatherings concerned with many fields of work will always be called for. For clearly stating and actually promoting knowledge, meetings of smaller groups of specialists are more important, and they have become therefore more and more popular, for a t them i t is possible t o restrict the number of lectures and to find time for thoroughly discussing the problem in question. An excellent example of this type of meeting is the one in review. The lectures delivered a t the Symposium treated mainly the stability of hydrophobic colloidal solutions and emulsions, the electrical properties of their particles, and the protecting and sensitizing action of hydrophilic colloids. The younger generation of colloidal chemists, more theoretically minded than the older oneHolland may claim to possess a very active and successful group-is right in trying t o apply new theoretical conceptions, e.g., Debije-Hueckel’s theory, to these problems. The discussion shows that this theory cannot explain in a simple and straightforward way the difficulties of the electrical double layer. Several speakers, representing fairly different points of view, acknowledged that even with poorly hydrated colloids the hydration of the ions, BO strongly depending upon their size and charge, is most important and may be decisive for the distribution of the ions on the surface of the particles. This specific nature and hydration of the ions is a cardinal point not covered by Debije-Hueckel’s theory. Perhaps the time has come when conceptions concerning hydration, as they are discussed by Bernal and Fowler (Journal qf Chemical Physics, 1933), may be extended and applied to these colloidal systems.
H. FREUNDLICR.
